JPS59143632A - Laminated film and manufacture thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a laminated film and a method for producing the same, and specifically, it does not require adhesives or pre-treatment of the raw film at the production stage, has high mechanical strength and pressure bonding force, and has a superior appearance. The present invention relates to a laminated film that is excellent in terms of quality, etc., and an efficient manufacturing method thereof.

Conventionally, films of thermoplastic resins such as polyolefins and polyamides have been subjected to uniaxial or biaxial stretching in order to increase their strength, particularly mechanical strength. However, the film obtained by -axis stretching has the disadvantage that the mechanical strength is significantly directional, and there are cracks in the direction of stretching. In addition, there are the tenter method and the inflation method as manufacturing methods using biaxial stretching, but the tenter method requires expensive manufacturing equipment and advanced technology. On the other hand, the inflation method has the disadvantage that it is not possible to impart sufficient orientation to the film, and furthermore, the uniformity of orientation is poor, making it impossible to obtain a film with excellent strength. In order to overcome these drawbacks, it has been proposed to laminate two or more uniaxially oriented resin films by laminating them together so that their orientation directions cross each other. As for the bonding methods here, ■ A method of bonding with an @ type adhesive, and a method of bonding with a zero-reactivity adhesive.

There are methods such as ■method using hot-melt adhesive, and ■melt pressure bonding method. However, methods (1) and (2) require an adhesive application step and a curing step, and have drawbacks such as the smell of a solvent. In addition, methods (1) and (2) have the essential drawback that the uniaxially stretched film shrinks when heated above its melting point, causing wrinkles in the laminated film and reducing the effect of cross-laminating stretched and oriented films. .

In order to improve these shortcomings, a method has been proposed in which the bonding is carried out using self-adhesive force without using an adhesive at a temperature below the melting point, but this method has low adhesive strength and requires pre-treatment using corona discharge. is required (Special Public Interest Publication in 1982)
-6505 publication). Furthermore, in order to increase the adhesive strength, a method has been proposed in which the film is passed between rolling rolls to reduce the film thickness and then press-bonded (Japanese Patent Publication No. 4'j 1982-98065). However, this method cannot be applied to precious films;
It is difficult to adjust the thickness, resulting in high production costs, and it also has the disadvantage that it is not possible to obtain a laminated film from films with different rolling properties.

As mentioned above, there is no known practically satisfactory laminated film with high strength, in which films oriented in the -axis direction are stacked so that their orientation directions intersect, or a method for producing the same. Furthermore, since conventional laminated films are adhesive on the entire surface, high-speed tear propagation resistance is not satisfactory.

In view of the above-mentioned prior art, the present inventors have developed a laminated film with satisfactory properties and an efficient method thereof. +! After extensive research into manufacturing methods, we have completed the present invention.

That is, the present invention is a laminated film (first film) formed by overlapping two or more thermoplastic resin films oriented in a uniaxial direction and partially pressing them regularly or irregularly by applying a force in the direction of each orientation (crossing each other). invention) and two or more diagonally oriented thermoplastic resin films are superimposed so that their orientation directions intersect, and then they are partially thermocompressed using a roll having unevenness at a temperature below the melting point of the film. A method for producing a laminated film (second invention) characterized by
It is.

The thermoplastic resin used in the present invention can be any commonly used thermoplastic resin without particular limitation. Examples of this thermoplastic resin include polyolefin pomopolymers or copolymers (polyethylene is low density polyethylene, medium density polyethylene, high density polyethylene, 4'' polypropylene, polyolefin modified with unsaturated acids or their anhydrides). etc.), polyestertyl, 4ζ-lyamide, polyvinylidene chloride, polyethylene terephthalate, etc., or mixtures thereof.Even thermoplastic resins to which rubbers or the like are added as necessary can be applied to the present invention. Be able to do it.

The thermoplastic resin film used in the present invention has the above-mentioned thermoplastic νf
It is obtained by using a monomorphic resin as a raw material, molding it into a film, and, if necessary, further stretching it in one direction. The film forming force>i is usually determined by an inflation method, a T-die method, etc., and there is no particular restriction on which method is used.

In addition, in order to impart orientation to the obtained film, the film is stretched in one direction, preferably at a draft ratio of 5 to 5.
Stretching treatment may be performed at about 2' OO, and in this way a thermoplastic resin film oriented in the desired uniaxial direction can be obtained. To give an example of a specific method, various thermoplastic resins are heated at a blow ratio of 0.8 to 2 and a draft ratio of 5 to 5.
Inflation molded with 200, thickness 20-200μ
A single-layer or multi-layer blown film of preferably 50 to 100 μm is obtained, and the obtained cylindrical film is cut into a spiral shape at 25 to 70 degrees in the longitudinal direction as a raw film (obliquely oriented flat film) according to the present invention. A thermoplastic resin film used for this purpose is obtained.

Usually, the thermoplastic resin film is a single layer, but it may be multilayered if necessary. In the case of multiple layers, when molding into a laminated film, it is extremely effective to use a low melting point resin or a good pressure bonding resin for the inner layer, as this will improve workability in manufacturing the laminated film and increase the pressure bonding force. It is.

Two or more uniaxially oriented thermoplastic resin films must be stacked so that their orientation directions intersect. This is to eliminate the drawback that the strength of the laminated film obtained after pressure-bonding decreases due to the orientation bias p, etc., when the layers are stacked so that their orientation directions intersect. In addition, in the present invention, overlapping so that the orientation directions intersect means that the orientation directions of the layers that are not in instant contact (for example, the outer layers on both sides of the intermediate layer in the case of 6 layers) in a multilayer laminate of two or more layers are Even if they are in the same direction, the requirements are satisfied as long as the orientation directions of adjacent layers cross each other.

Further, the films to be superimposed may be the same thermoplastic resin films or may be different.

However, it is preferable to use the same thermoplastic resin film from the viewpoint of pressure bonding workability and pressure bonding force.

The laminated film in the first invention is formed by partially pressing two or more thermoplastic resin films stacked together as described above. Here, "partially crimping" means crimping the overlapped films irregularly or in a regular manner without fully crimping them together.
According to IIJ, this means crimping while leaving the unbonded part.

Therefore, this laminated film has many portions where adjacent films are not bonded to each other, and the existence of these non-bonded portions greatly contributes to the excellent physical properties of the laminated film of the present invention. The crimped part formed by such partial crimping may have an irregular shape, but it may have a continuous V-shaped grid shape as shown in Figure 1, or a shape with regular points as shown in Figure 2. From the viewpoint of the strength of the laminate, it is preferable that the crimped portions are uniformly scattered throughout the film, forming so-called spot-like patterns. In particular, if the crimp part is in the form of a lattice, the number of lattice meshes on the film is 50 to 1o.
ooo pieces/cr! , preferably 10Q to 1000 pieces/d
If the crimped part is in the form of scattered spots, the number of spots on the film should be 50 to 10,000.
pieces/Cn11 preferably 100 to i ooo pieces/cII
It is common to do so.

In the laminated film of the first invention, which is partially crimped, the laminated films are not completely integrated compared to those which are fully crimped, so even if tearing force is applied to the film for some reason, Laminar cracking occurs and tearing is effectively prevented, resulting in significantly greater tear strength.

The laminated film according to the first invention as described above can be manufactured very efficiently according to the manufacturing method of the second invention. That is, according to the method of the second invention, the diagonally oriented thermoplastic resin films as described above are stacked so that their respective orientation directions intersect, and the film is partially heated using a roll having unevenness at a temperature below the melting point of the film. A laminated film can be produced by thermocompression bonding.

A roll with unevenness usually refers to an embossing roll (
Various patterns can be considered for the surface of the crimping part. (See Figure 1) 1. It is sufficient that the surface irregularities of this roll are formed in a lattice shape, and the FJ has a spot-like shape with scattered dots.The moving part (See Figure 2) teeth,
It is better to use a boss roll with a large number of uniform markings on the roll surface.

The surface of Eyu Bosroll has a regular pattern like this)2
Alternatively, it may have an irregular pattern, for example, a pattern similar to crushed ice blocks. However, from the viewpoint of MII of such an embossing roll and the strength of the laminated film that is damaged, it is desirable to have a regular pattern.

The method of the second invention uses various devices a? )' However, for example, as shown in FIG.
, 1', the original film of diagonally oriented thermoplastic resin is superimposed one thickness on backup roll 2 so that the orientation directions intersect with each other, and then the thermoplastic resin is heated at a temperature below the melting point of the thermoplastic resin. heating roll 5 heated to
By heating and press-bonding with an embossing roll (engraved roll) 4 having a predetermined uneven pattern, it is possible to produce a laminated film having a crimped portion having a shape corresponding to the uneven pattern.

As described above, the laminated film of the present invention does not require an adhesive or special pretreatment such as corona discharge treatment during lamination, and can be made into a laminated film regardless of the thickness of the film. According to the method of the second invention, it is easy to operate, and it is possible to produce a laminated film with good workability. The resulting laminated film is layered in a manner that intersects the orientation direction to improve its strength, and it has a high-speed tear stopping effect even though the area of the crimped part is small because it is partially crimped instead of entirely crimped. This laminated film is much stronger than conventional ones. Furthermore, it has the advantage of not only good strength but also good appearance, less light reflection, and less dirt. Therefore,
The present invention can be effectively utilized in the field of packaging or coating materials.

The present invention will be explained below with reference to Examples.

Fruit bd Mureri 1 to 4 A three-layer film was molded by the inflation method using the thermoplastic resin shown in Table 1 to obtain a cylindrical film with a thickness of 50 to 50 μm (Dielip 1).

flow ratio 1.5). Next, the longitudinal direction of the cylindrical film,
.

The film was cut into snomiral shapes at angles of 60 degrees and 40 degrees to obtain original films. The obtained films were stacked on top of each other with the inner layer film side facing in the opposite direction, and were pressed together at a predetermined temperature using an inverted grain-engraved roll having 400 lattices/i. Table 1 shows the measurement results of the obtained laminated film.

Example 5 High density polyethylene (density α955 Li-/cff
Example 1 except that a single layer film of l, MIo, oslit/1oe) was used and the pressure bonding temperature was 120°C.
A laminated film having a thickness of 137-80μ was obtained in the same manner as in steps 4 to 4.

・1・The ratio of one layer is inner: middle; outer - 1:13:1.

・2... Linear low density polyethylene (copolymerization K of 4-methylpentene-1, density α9237/F.

MI 2.4 jil-/10 minutes) e3- Ethylene-propylene diene rubber (contains propylene M28% by weight, contains ethylidene norbornane b
k1siAM%, Mooney viscosity M L H+.

(100°C) 90) +14... Polypropylene (block type, density 091y-/crAIM engineering toe/10 minutes)・5...
・High 'J JJt polyethylene (density α9557-/d
.

MI0.05g/10min) *6・= Polypropylene (density 0.91P/cr
A, MI0, 6'i-710 minutes) -t ---Compliant with JIS Z1702-B... Film inject method (fixing the film in a link shape,
The film was extracted 11 times with a pendulum with a 1-inch impact head.
Measure the energy required for that.1-. ) (Using Toyo Seiki Seisakusho film impact tester)

[Brief explanation of the drawing]

FIGS. 1 and 2 are explanatory diagrams showing the mode of partial pressure bonding of the laminated film of the present invention. FIG. 5 is a schematic diagram showing the apparatus 1j used in the method of the present invention. 1.1'...Original roll, 2 Bank up roll. Roll, heating roll, 4... engraving roll, 5... winding, patent applicant Idemitsu Petrochemical Co., Ltd. Figure 1 Figure 2 Figure 3 Procedural amendment (voluntary) June 1980 If, Commissioner of the Japan Patent Office Kazuo Wakasugi 1, Indication of the case Patent application 18068/1982 Name of the invention: Laminated film and its manufacturing method & person making the amendment Relationship with the case Patent applicant: Idemitsu Petrochemical Co., Ltd. 4, Agent: 104 Chuo, Tokyo 1-1-10-5, Kyobashi-ku, 1-1-10, ``Torre subject to correction: approximately 5 to 200'' is corrected to ``Stretching ratio: approximately 1.5 to 4.'' (2) From the 5th line from the bottom to the last line on page 15 [middle 1]
・・Film impact method・・・use)” for “$8
...Compliant with JISF-8134". (3) Table 1 on page 14 of the same salary is corrected as follows. /′

Claims (1)

[Claims] (1+ - A laminated film formed by stacking two or more thermoplastic resin films oriented in a uniaxial direction such that their orientation directions intersect and partially pressing them regularly or irregularly. (2) The thermoplastic resin film is polyolefin. The laminated film according to claim 1, which is a single layer or multilayer film of polyester, polyamide, or a mixture thereof. (3) The crimped portion is formed in a lattice shape. The laminated film according to claim 1, which is a laminated film according to claim 1. (4) The number of meshes in the grid of the crimp portion formed in a grid shape is 50.
The laminated film according to claim 6, wherein the number of particles is 100 to 100 pieces/d. (5) The laminated film according to claim 1, wherein the crimped portion is formed in the shape of a coralline. (6) The number of spots formed in the shape of spots on the crimped part is 50.
The laminated film according to claim 5, which has a density of 10,000 to 10,000 pieces/cri. (7) Two or more obliquely oriented thermoplastic resin films are stacked so that their orientation directions intersect, and then they are partially thermocompressed using a roll with unevenness at a temperature below the melting point of the film. A method for producing a laminated film characterized by: (8) The thermoplastic resin film is polyolefin. 8. The method for producing a laminated film according to claim 7, which is a single layer or multilayer film of polyester, polyamide, or a mixture thereof. (9) The manufacturing method according to claim 7, wherein the roll having unevenness forms a lattice pattern. 10. The manufacturing method according to claim 9, wherein the number of meshes in the grid of the roll having unevenness formed in a grid pattern is 50 to 10,000 pieces/ciI. The manufacturing method according to claim 7, wherein the roll having αυ unevenness forms a spotted pattern. 12. The manufacturing method according to claim 11, wherein the number of spots on the roll having unevenness formed in a dotted pattern is 50 to 1oooo spots/cllt.